Machining operations of various configured metal workpieces are a standard throughout the world, and are especially common with vehicular components. These operations include boring, drilling, milling, or other metal cutting turning operations executed with various types of cutting tools. As the cutting tool removes material, “chips” are created. In theory, the chips that are rather short, and fall to the bottom of the machining center, away from the tool and workpiece. However, in practice, these chips can become very long, stringy, and curly, and create enormous machining issues. Difficult-to-break chips are often generated in machining high toughness or soft gummy materials, such as pure aluminum, pure copper, aluminum alloys, copper alloys, low carbon steels, and stainless steels.
These continuous and curly shaped chips have long been known as a serious problem by-product of cutting operations. Long stringy chips can collect themselves into large bundles of razor-wire-like material (“hay”) that must be cleaned out of the machines multiple times per shift. Additionally, these chips can scrape or otherwise mar the machined surface of the workpiece if they are allowed to remain intact during the machining operation. They can wrap themselves around the tool during machining and eventually slip under the tool nose, creating gouges in the workpiece.
While the formation of these long chips when using conventional manually operated machine tools may be of a slightly lesser concern, since the chips can be readily removed by the operator during their formation, there are still safety hazards because the long curling chips often form growing bundles which can cut the operator's skin while attempting to remove them. However, when using a computer programmed or other automated machine tools, especially, when the machine tools are enclosed in a housing, access to the workpiece for breaking or removing the chips is restricted so as to present a problem with to the respect to the generation and removal of the long continuous chips.
Computer numerically controlled (CNC) operations are pre-programmed machining steps for metal cutting operations performed sequentially on a workpiece spindled opposite a turret, typically within a cabinet. CNC machining requires the control of a number of variables in order to attain the maximum productivity for a given cutting operation. The reliability of machining operations is an essential aspect of modern automatic manufacturing systems. In the case of turning operations in which unbroken chips are the major obstacles for automation, reliability implies chip control as a major aspect.
Scribing a part for chip control is a simple first step before automated CNC machining; however, it does much more. Removing the chip control problem allows for dry machining with lower-cost and a more predictable tool life. It also reduces the number of machining passes needed, again slashing costs. Also, since the chips are controlled and no longer wrapping themselves around the tools and fixtures, then CNC based automated machine loading and unloading, automatic gauging, and automatic tool changing is possible without fouling.
Using the same CNC tool to prescribe a grooved pattern into a raw part that extends down into the part to create an interrupted cut during turning effectively and efficiently effectuates separation of the chips for total chip control. The distance between scribes or grooves on the part can be adjusted to define the actual chip size, and the depth of the scribe is adjusted to match the amount of material removal needed for the final part dimensions. Additionally, using the same automated tool, rather than adding a manual tool, or breakers, or localized heating, greatly decreases overall cycle time as would be understood by one skilled in the art.
U.S. Pat. No. 5,384,446, issued to Edward D. Rutkowski, attempts to overcome the problems described above by providing a path etched into a workpiece by a laser beam. The laser beam defines a pattern of chip breaking points and controls the length of the chips removed from the workpiece via a separate known machine-cutting element. The material is cut away from the workpiece along a second path, which periodically intersects with the first path. The Rutkowski suffers from at least one deficiency in that a separate laser device is introduced into the machining operation, which takes additional space, and significantly increases cost. The laser is a separate machine with a robot arm moving a fluent beam along the first path.
The present disclosure is directed to overcoming one or more of the problems set forth above.